表皮生长因子增强TPN对放射性肠炎大鼠EGFR及其基因表达的影响

放射性肠炎应用ＴＰＮ时，肠粘膜由于缺乏肠道营养刺激而萎缩，加重细菌易位。表皮生长因子（ＥＧＦ）可促进胃肠道粘膜上皮细胞的有丝分裂，增加蛋白质及ＤＮＡ合成，调节细胞防御和胃肠道分泌，对维持胃肠道的完整性具有重要作用。ＥＧＦ的许多生物效应尚不十分清楚。本研究旨在观察ＥＧＦ增强ＴＰＮ对放射性肠炎小肠ＥＧＦＲ及其基因（ＥＧＦＲｍＲＮＡ）表达的影响，并探讨其与谷氨酰胺代谢及肠粘膜屏障的关系。研究表明，治疗放

The effects of EGF on the expression of EGFR and EGFR m RNA in radiation enteritis rat during the TPN

There is marked intestinal atrophy in the radiation enterits of intravenously fed (TPN) rat,because of shortof stimulate of luminal nutrition.This damages the gut mucosa and leads to bacterial translacation(BT) from gut tract.But the intestinal mucosa appears in dramatic proliferative response to EGF(Epidermal Growth Factor) .EGF has been showed to elicit an important effect on the preservation of gut integrite,including regulate intestinal cell proliferlation,enhanced protein and DNA synthesis,and regulated the gastrointestinal mucosal resistance and secretion.The physiological role of EGF was not clearly understood. Some studis shows thatthe physiological role of EGF may depend on target tissue changes in the expression of EGFR and EGFR gene.We now report that the EGF can made advantage effect on radiation enteritis and its mechanism during TPN.After 9.5 Gy of60 Co abdominal radiation (AR) rats were separated randomly into four groups:Group A as nomal group (sham operation only n=8) ;Group B(n=1 8) ,AR+ sham operation;Group C(n=1 8) ,AR+ TPN;group D(n=1 8) ,AR+ TPN+ EGF;Nine rats were selected at random from each group in day 7and 1 4following irradiation.Rats were observed for .Intestinal glutamine extraction,mucosa DNA,the expression of EGFR and EGFR m RNA were determined.We conclude that(1 ) EGF- enrich TPN stimulated intestinal mucosa EGFR and EGFR m RNA expression increased significantly;(2 ) EGF enhance protein and DNA synthesis.The mechanisms of EGF action are that:EGF exerts its effects after binding to EGFR,a membrane- bound glycoprotein receptor,binding to this receptor activates an intrinsic tyrosine kinase activity.It could not only providing radiation entritis rats intestinal have a good rest and to assist in the recovery from the radiation injury,but induce the expression of EGFR and EGFR m RNA which could regulate intestinal glutamene uptake,prevented severe intestinal mucosa atrophy and bacterial translacation from gut.